With the rapid development of optical communication, particularly the optical communication network, a 100% optical system eliminating optical/electrical conversion has become the mainstream of the development. An optical communication network requires direct processing of the optical signal per se, such as controlling the intensity of the optical signal by means of an optical attenuator so as to perform dynamic manipulation of signals at each channel to an appropriate degree, to maintain optimum performance and safety of the optical transmission active and passive components, to simplify the system. The switching between different optical paths relies on optical switches. A high-performance, low-cost optical signal processing device has, thus, become an essential component in such system.
Most conventional optical signal processing devices use switching devices of the mechanical types, where such mechanical switches usually involve high production cost resulted from the precision alignment and calibration of optical paths, inability of being produced in batches, and the disadvantages of being easily worn. The use of micro-mechanical-electrical system (MEMS) to produce optical signal processing devices can not only dramatically reduce components sizes, but also allow batch production by adopting processes similar to those adopted in semi-conductors, while providing high production precision and reducing production cost at the same time.